The present invention relates to a method of producing extrusions of profiled strands from elastomeric materials with sealing lips along portions of its curved outer contour. The present invention also relates to an apparatus for carrying out such a method.
Profiled strands which are used, for example, for framing and binding window panes of vehicles and buildings, are generally produced in practically infinite lengths using the elastomeric material mixture, which is predominantly in the plastic state, extruded but of an appropriately shaped nozzle or orifice. A particular difficulty ensues from the variously raised requirement for the removal of partial sections of the sealing lips which are uniformly formed on the profiled strand. The subsequent mechanical cutting of the already produced profiled strands is time consuming and uneconomical, and has the additional drawback that unusable, polymerized elastomeric material is obtained. German Pat. No. 1179358 discloses cutting out sections of, extruded profiled strips by means of a power-operated cutting tool using a given pattern immediately after they emerge from the orifice of the extruder. However, since the known apparatus, without regard to the cross sectional shape of the profiled strands and their final shape, which is determined by the peculiarities of the respectively prevailing mounting conditions, is always only set for a linear cutting guidance as well as for the formation of linearly extending cutting edges.
It is therefore an object of the present invention to produce extruded profiled strands which can be used for framing and sealing purposes, and which are alternately provided with uniformly formed-on and eliminated sealing lips; in this connection, the transitions between the various sections are to be formed in precise conformity to the arcuate curved outer contours of the strands.